Endoplasmic reticulum stress markers in tularemia: a case-control study

Tularemia is a zoonotic infectious disease caused by Francisella tularensis. It is transmitted by rodents and results in an infectious disease characterized by lymphadenopathy. This study aims to evaluate the role of endoplasmic reticulum (ER) stress in patients with tularemia. This prospective, case-control study was conducted between June and August 2024 at the Infectious Diseases and Clinical Microbiology Clinics of Sivas Cumhuriyet University Hospital, Sivas, Turkey. The study included 40 patients aged 18 years and older diagnosed with tularemia. The control group comprised 30 healthy individuals. The serum levels of ER stress markers (EIF2α, GRP78, and CHOP) were compared between patients and control groups. The mean age of the patients was 44 ± 16 years, and 72.5 % (n = 29) were female. The control group had a mean age of 37 ± 12 years, and 36 % (n = 11) were female. The most common clinical form of tularemia was oropharyngeal (82.5 %, n = 33). Levels of EIF2α, GRP78, and CHOP were significantly higher in the tularemia patient group compared to the control group (p < 0.001). Although ER stress protein levels were higher in patients who did not require lymph node dissection than in those who did, the difference was not statistically significant. Additionally, no significant difference was observed in ER stress protein levels between patients who responded to treatment and those who did not. The results of this study indicate that ER stress molecules such as CHOP, EIF2α, and GRP78 exhibit significant increases during tularemia infection. These data support the role of the ER stress pathway in the pathogenesis of tularemia.